Derrick.



PATENTED APR. 17, 1906.

S. P, MITCHELL.

DERRICK.

APPLIOATION FILED JAN. 21, 1905.

3 SHEETS-$HBET 1.

PATENTED APR. 1'7, 1906.

S. P. MITCHELL DERRICK.

APPLICATION FILED JAN. 21, 1905.

3 HEETSSIS1BT 2 PATBNTED APR. 17, 1906.

s. P. MITCHELL.

DERRICK.

APPLICATION FILED JAN. 21. 1905.

3 SHEETS-SHEET 3.

mwah mgv.

SAMUEL P. MITCHELL, OF PHILADELPHIA, PENNSYLVANIA.

DERRICK.

Specification of Letters Patent.

Patented April 17, 1906.

Application filed January 21, 1905. Serial No. 242,043.

To a whom it may concern:

Be it known that I, SAMUEL P. MITCHELL, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain Improvements in Derricks, of which the following is a specification.

This invention relates to steel derricks; and it has for its leading object to produce a construction which by means of the special shapes employed provides for the use of long struts having the large median cross-section that is required for withstanding the bending strains to which they are subjected and ends of such smaller cross-section as to admit of properly forming the connections which are required to be made therewith. It is sometimes necessary to use masts of, say, eighty feet length with proportionately long booms and stiff legs in which an intermediate crosssection of, say, eighteen inches is requisite to withstand the bending strains, while so large a section is unnecessary and undesirable for making the connections at the ends. In such constructions it is desirable to be able to vary the lengths of the struts for the accommodation of the work in hand, and to this end, as well as to afford facility in manufacturing and handling, the struts are formed in separable sections joined by an improved splice which provides adequate strength and is readily made.

The characteristic features of the invention will appear from the following description and the accompanying drawings in illustration thereof, of which Figure 1 represents a side elevation of a derrick embodying improvements of my invention. Fig. 1 represents a plan view of a channel made in accordance with my invention. Fig. l -represents a side view of a pair of such channels arranged in the relative positions they occupy in a strut. Fig. 2 represents a plan view of the supporting members for the mast and stiff legs. Fig. 3 represents a plan view of the stiff legs. Fig. 4 represents a plan, and Fig. 5 a side elevation, of the outer end of the boom. Fig. 6 represents a plan, and Fig. 7 a side elevation, of the inner end of the boom. Fig. 8 represents a longitudinal sectional view illustrating the splice. Fig. 8 represents a longitudinal sectional view taken through the splice at right angles to the view shown in Fig. 8.

angles to each other of sections of the mast; and Fig. 11 represents a plan, and Fig. 12 a sectional view, of the spider.

As shown in the drawings, the supportingframe comprises sills 1, fixed to a base 2 and having the counterweight platforms 3 secured thereto. A foot-block 4 is supported by the base and supports a mast 5, which has a movable bearing thereon. Stiff legs 6 for supporting the mast are provided with goosenecks 7, by which they are secured to the mast by a pin 8, being secured to the sills by pins 9. This structure may be stiffened by means of guys 10, connecting the tops of the stiff-legs with the base. A shoe 11, secured to the foot of the mast, has the foot of a boom 12 connected thereto by a pin 13. A hood 14 at the top of the mast, is connected by the topping-fall 15 with a hood 16 at the top of the boom, the latter hood having the lifting-- fall 17 connected therewith.

The end sections of the mast 5 comprise the tapered pressed-steel channels 18, having the flanges 18 thereof converging toward the mast ends, and the plates 19, tapering toward the mast ends, secured to the flanges. These end sections of the mast may be spliced directly together by having the channels connected by the channel-sections 20 and the plates connected by the plates 21. Similarly to the mast the end sections of the boom comprise the tapered pressed-steel channels 22, having flanges 22 converging toward the boom ends, and the plates 23, tapering toward the boom ends, connected to the flanges of the channels. The splice between the sections comprises channel-sections 20 and the plates 21. To reduce the cutting and wearing of the tackle-line by the flanges, the planking 22 is placed between the flanges 22, providing a filler for the channel. .In like manner the end sections of the stiff legs comprise the tapered-pressed steel channels 25, with the flanges 25 thereof converging toward the ends of the legs, and the tapered plates 26, converging toward the ends of the legs, secured to the channel-flanges, the channels being connected by the channel-sections 20 and the plates by the plate-sections 21.

Channels, such as shownin Figs. 1 and 1 are preferably used in the mast, boom, and

I stiff legs in which the web has the wide rectangular end section 18*, the comparatively narrow rectangular end section 18 and the Figs. 9 and 10 represent elevations at right i tapering intermediate body or intermediate IIO section 18", the end sections extending in parallel directions and at an angle to the intermediate section, which is arranged diagonally thereto. The flanges of the channels comprise the parallel end sections 18, joined to the web-section 18, the parallel end sections 18 joined to the web-section 18 and the intermediate sections 18 joined to the web-section 18 and converging from the sections 18 to 18 the end sections 18 and 18 eXtendingin parallel directions and at an angle to the intermediate sections 18 which are arranged diagonally thereto. It will be understood that the plates connected to the flanges of the channels have rectangular end sections joined by a tapering intermediate section conforming to the arrangement of the channels shownin Fig. 1 This construction provides struts having ends which are pyramidal frustums terminating in p ar allel members suitable for the convenient engagement of the shoe 11 at the foot of the mast, the hoods 14 and 16 at the tops of the mast and boom, the plates 12 at the foot of the boom, and the plates 26 at the foot of the stiff legs.

As shown in Figs. 8 and 8 in forming the strut splice, whether in the mast, boom, or stiff legs, the channels 22 on either side are brought into abutment and secured together by riveting therethrough and through the externally-placed splicing-channels 20 and the internally-placed splicing-plates 20. The plates connecting the channels, as 23, whether in the boom, mast, or stiff leg, have spaces, as 23, left between them to permit access to the interior of the strut for bolting through the splice members 20 and 20. These spaces are closed by the filler-plates 21, which fit therein and engage the channelflanges, the filler-plates being riveted to the cover-plates 21. The plates 21 are connected to the plates 23 by bolts 27, which have their heads 27 engaged in corresponding sockets of the plates 28 within the strut, the plates and bolts being supported by chairs 29, connected by the bolts 29 to the plates 23. It will be understood that this joint can readily be opened and. closed and that by means of it the end sections of the strut are adapted for connection with an intermediate section or sections when it is desired to lengthen the strut.

To guy the mast, a spider 30 is employed, comprising the plates 30, riveted together. In the spider is formed the central aperture 31, which receives the pin 8 for holding it to the top of the mast and the siX peripheral slots 32 for engagin shackles 33, the latter carrying sheaves 34 "or holding the guy-lines 35. The slots are of such length and so arranged that the spider is adapted for use with either four or six guys and so that the guys will divide the spider into quadrants or seXtants, the slots permitting the shackles to be shifted as required for this purpose.

It will be understood that while the pressedsteel channel specified is the preferred shape a built-up channel or other shapes may be employed without departing from the spirit of my invention.

Having described my invention, I claim 1. In a derrick, a strut having separable tapered end sections each comprising members with converging flanges and tapered plates secured to said flanges and splicing members lapping and. secured to said first members, substantially as specified.

2. In a derrick, a strut comprising a plurality of channeled sections each having a web with parallel end sections having parallel sides and parallel flanges thereon, said web having an intermediate portion arranged diagonally to its ends and having tapered sides with tapering flanges thereon, substantially as specified.

3. In a derrick, a strut having tapered end sections comprising pressedsteel channels having converging flanges and tapered plates secured to said flanges and splicing members for securing said end sections together, substantially as specified.

4. In a derrick, a mast having separable tapered end sections comprising members with converging flanges and tapered plates secured thereto, in combination with a boom having separable tapered end sections comprising members with converging flanges and tapered plates secured thereto, substantially as specified.

5. In a derrick, a mast having tapered end sections comprising members with converging flanges and means for securing said mast members together, in combination with a boom having tapered ends comprising members with. converging flanges and means for securing said boom members together and a stay connected to said mast, said stay having tapered end sections comprising members with converging flanges and. means for connecting said stay members together, sub stantially as specified.

6. In a derrick, a mast having tapered end sections comprising pressed-steel channels having converging flanges and tapered plates secured to said flanges, in combination with a boom having tapered ends comprising pressed steel channels having converging flanges and tapered plates secured to the flanges of said boom-channels, substantially as specified.

7. In a derrick, a mast comprising pressedsteel shapes with converging flanges, and means for securing said shapes together, in combination with aboom comprising pressedsteel shapes with converging flanges and means for securing said last-named shapes together, and a stiff leg comprising pressed-steel shapes with converging flanges and means for securing said last-named flanges together, substantially as specified.

IIO

8. In a derrick, a strut having sections connected by a joint comprising abutting flanged shapes on either side thereof, splicing members connecting said flanged shapes, plates connecting said flanged shapes and having an opening between them for access to the interior of said strut, and a splice-plate covering said opening and connected to said strut, substantially as specified.

9. In a derrick, a strut having sections connected by a joint comprising abutting flanged shapes on either side thereof, interior and exterior splicing members connecting said shapes, plates connecting the flanges of said shapes andproviding an opening for access to the interior of said strut, a filler-plate fitting said opening, a cover -plate connected to said filler plate, bolts for securing said cover-plate to said strut, and means Within said strut for holding said bolts, substantially as specified.

10. In a derrick, a mast, and a spider secured to said mast, said spider being provided With slots extending in the direction of its periphery, substantially as specified.

11. In a derrick, a spider having slots eX- tending in the direction of its periphery, shackles engaged in said slots, and sheaves carried by said shackles, substantially as specified.

In testimony whereof I have hereunto set my hand, this 20th day of January, A. D. 1905, inthe presence of the subscribing Wit- IIBSSBS.

SAMUEL P. MITCHELL. Witnesses: ROBERT JAMEs EARLEY, UTLEY E. CRANE, Jr. 

